Paulo Artaxo

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Verified

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• PhD
• Professor at University of São Paulo

In central Amazonia, aerosol sources, weather, and chemical processes create a highly variable aerosol population. The aerosols' optical properties, shaped by composition and size, determine sunlight interaction and the regional radiation budget. Previous studies observed differences in the particles' physical properties during smoke events and des...

The Amazon rain forest plays an important role in the biogeochemistry, water cycle, and climate of the South American continent and the Earth system. The Amazon Tall Tower Observatory (ATTO) has been established to study and quantify forest-atmosphere interactions under natural conditions, as well as the transformation of the Amazon ecosystem as a...

The Amazon rainforest is a unique environment to investigate aerosol properties with limited impact from human activities, further providing a new perspective to look at the aerosol characteristics in regions heavily affected by anthropogenic emissions. Obtaining the size distributions of nucleation mode particles in the atmosphere is key to unders...

As the impacts of climate change become increasingly evident, understanding the role of atmospheric aerosols in regulating Earth’s climate is crucial. Despite their significance, the optical properties of aerosols remain unclear to the general public and, particularly, to students in Physical and Earth sciences. This paper presents a didactic appro...

The Amazon, the world’s largest tropical forest, plays a critical role in the global carbon cycle. It has a large carbon pool and acts as a major carbon sink. However, in 2023–2024, a compound heatwave-drought (CHWD) event (HD2023) hit the Amazon region, resulting in extreme temperatures and soil moisture deficits, threatening the region’s carbon s...

In this study, we investigate atmospheric new particle formation (NPF) across 65 d in the Bolivian central Andes at two locations: the mountaintop Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto–La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We classified the days into four categories based on the intensity of...

This study analyzes spatial-temporal deforestation patterns in Amazonas using 36 years of land use and land cover changes . We identified contiguous deforestation patches for each year and characterized their evolution using two geometric metrics: compactness, related to the shape of the patch and equivalent radius, proportional to the deforested a...

New particle formation (NPF) in the tropical upper troposphere is a globally important source of atmospheric aerosols1, 2, 3–4. It is known to occur over the Amazon basin, but the nucleation mechanism and chemical precursors have yet to be identified². Here we present comprehensive in situ aircraft measurements showing that extremely low-volatile o...

Surface ozone monitoring sites in the tropics are limited, despite the risk that surface ozone poses to human health, tropical forest and crop productivity. Atmospheric chemistry models allow us to assess ozone exposure in unmonitored locations and evaluate the potential influence of changing policies and climate on air quality, human health and ec...

Atmospheric aerosol particles are essential for forming clouds and precipitation, thereby influencing Earth’s energy budget, water cycle and climate on regional and global scales. However, the origin of aerosol particles over the Amazon rainforest during the wet season is poorly understood. Earlier studies showed new particle formation in the outfl...

During the dry season, the Amazonian atmosphere is strongly impacted by fires, even in remote areas. However, there are still knowledge gaps regarding how each aerosol type affects the aerosol radiative forcing. This work characterizes the chemical composition of submicrometer aerosols and source apportionment of Organic Aerosols (OA) and Equivalen...

Climate change research is broad, diverse and constantly growing. Cross- and interdisciplinary understanding is essential for generating robust science advice for policy. However, it is challenging to prioritise and navigate the ever-expanding peer-reviewed literature. To address this, we gathered input from experts across various research fields t...

The Amazon rainforest plays a crucial role in the global climate system, acting as a major carbon sink and influencing regional and global weather patterns. Understanding the chemical composition of rainwater is essential for assessing the impact of anthropogenic activities, such as deforestation and industrial emissions, on atmospheric chemistry a...

Elevated ground-level ozone, a result of human activity, is known to reduce plant productivity, but its influence on tropical forests remains unclear. Here we estimate how increased ozone exposure has affected tropical-forest productivity and the global carbon cycle. We experimentally measure the ozone susceptibility of various tropical tree specie...

Plain Language Summary Human activities, such as smelting and oil combustion, release smoke and particles into the atmosphere. These particles often contain iron, which not only absorbs sunlight, contributing to atmospheric warming, but also serves as a nutrient for phytoplankton in various ocean regions. However, the precise extent of human‐induce...

The Metropolitan Area of São Paulo (MASP) in Brazil has reduced its vehicular emissions in the last decades. However, it is still affected by air pollution events, mainly in the winter, characterized as a dry season. The chemical composition of fine particulate matter (PM2.5) was studied in the MASP during a 100-day dry period in 2019. PM2.5 sample...

This study investigates the rain-initiated mixing and variability in the mixing ratio of selected trace gases in the atmosphere over the central Amazon rain forest. It builds on comprehensive data from the Amazon Tall Tower Observatory (ATTO), spanning from 2013 to 2020 and comprising the greenhouse gases (GHGs) carbon dioxide (CO2) and methane (CH...

The wet-season atmosphere in the central Amazon resembles natural conditions with minimal anthropogenic influence, making it one of the rare preindustrial-like continental areas worldwide. Previous long-term studies have analyzed the properties and sources of the natural Amazonian background aerosol. However, the vertical profile of the planetary b...

Aerosol particles are an important part of the Earth system, but their concentrations are spatially and temporally heterogeneous, as well as variable in size and composition. Particles can interact with incoming solar radiation and outgoing long wave radiation, change cloud properties, affect photochemistry, impact surface air quality, change the s...

AI is increasingly essential for tackling climate change. Satellite images and sensors produce a huge amount of data every second. They are compiled and analyzed with AI tools. Forecast models, weather, and global climate models, with highly complex physical parameterization, are explicitly calculated with AI, which also optimizes energy sources, r...

In this study, we investigate atmospheric new particle formation (NPF) across 65 days in the Bolivian Central Andes at two locations: the mountain-top Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto-La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We categorize days into four groups based on NPF intensity, deter...

Climate change research is broad, diverse and constantly growing. Cross- and interdisciplinary understanding is essential for generating robust science advice for policy. However, it is challenging to prioritise and navigate the ever-expanding peer-reviewed literature. To address this, we gathered input from experts across various research fields t...

This study introduces a first glance at Amazonian aerosols in the N–Dg–σ phase space. Aerosol data, measured from May 2021 to April 2022 at the Amazon Tall Tower Observatory (ATTO), were fitted by a multi-modal lognormal function and separated into three modes: the sub-50 nm, the Aitken (50–100 nm), and the accumulation modes. The fit results were...

Numerous studies globally have centered on atmospheric air pollution due to its profound health and climate effects. NASA’s AERONET (National Aeronautics and Space Administration - AErosol RObotic NETwork) network has been one of the world’s leading tools for accessing the physical properties of atmospheric aerosols from various sources, mainly ant...

The role of manganese (Mn) in ecosystem carbon (C) biogeochemical cycling is gaining increasing attention. While soil Mn is mainly derived from bedrock, atmospheric deposition could be a major source of Mn to surface soils, with implications for soil C cycling. However, quantification of the atmospheric Mn cycle, which comprises emissions from natu...

Criegee intermediates are reactive intermediates that are implicated in transforming the composition of Earth’s troposphere and in the formation of secondary organic aerosol, impacting Earth’s radiation balance, air quality and human health. Yet, direct identification of their signatures in the field remains elusive. Here, from particulate and gas-...

Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooli...

Surface ozone monitoring sites in the tropics are limited, despite the risk that surface ozone poses to human health, tropical forest, and crop productivity. Atmospheric chemistry models allow us to assess ozone exposure in unmonitored locations and evaluate the potential influence of changing policies and climate on air quality, human health, and...

Aerosol particles are an important part of the Earth system, but their concentrations are spatially and temporally heterogeneous, as well as variable in size and composition. Aerosol particles can interact with incoming solar radiation and outgoing long wave radiation, change cloud properties, affect photochemistry, impact surface air quality, and...

The Amazon Basin, which plays a critical role in the carbon and water cycle, is under stress due to changes in climate, agricultural practices, and deforestation. The effects of thermodynamic and microphysical forcing on the strength of thunderstorms in the Basin (75–45°W, 0–15°S) were examined during the pre‐monsoon season (mid‐August through mid‐...

This study investigates the rain-initiated mixing and variability in the concentration of selected trace gases in the atmosphere over the central Amazon rain forest. It builds on comprehensive data from the Amazon Tall Tower Observatory (ATTO), spanning from 2013 to 2020 and comprising the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH...

A study on aerosols in the Brazilian subequatorial Amazon region, Tangará da Serra (TS) and Alta Floresta (AF) was conducted and compared to findings in an additional site with background characteristics (Manaus, AM). TS and AF counties suffer from intense biomass burning periods in the dry season, and it accounts for high levels of particles in th...

As mudanças climáticas estão afetando significantemente todos os biomas brasileiros. De maneira diferenciada, todos os nossos biomas, como Amazônia, Cerrado, Pantanal, Pampas e Caatinga, estão sendo impactados, tanto pela ação humana de mudança do uso do solo, quanto pela mudança climática. A resiliência de cada um de nossos biomas está sendo afeta...

Interactions between atmospheric aerosols, clouds, and precipitation impact Earth's radiative balance and air quality, yet remain poorly constrained. Precipitating clouds serve as major sinks for particulate matter, but recent studies suggest that precipitation may also act as a particle source. The magnitude of the sources versus sinks, particular...

The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering diverse environments from pristine to highly polluted conditions. We show that the effective ae...

Manganese (Mn) is a key cofactor in enzymes responsible for lignin decay (mainly Mn peroxidase), regulating the rate of litter degradation and carbon (C) turnover in temperate and boreal forest biomes.While soil Mn is mainly derived from bedrock, atmospheric Mn could also contribute to soil Mn cycling, especially within the surficial horizon, with...

The Amazon Basin is frequently influenced by transatlantic transport of African dust plumes during its wet season (January–April), which not only interrupts the near-pristine atmospheric condition in that season, but also provides nutrient inputs to the Amazon rainforest upon deposition. In this study, we use the chemical transport model GEOS-Chem...

The Amazon Basin, which plays a critical role in the carbon and water cycle, is under stress due to changes in climate, agricultural practices, and deforestation. The effects of thermodynamic and microphysical forcing on the strength of thunderstorms in the Basin (75-45° W, 0-15° S) were examined during the pre-monsoon season (mid-August through mi...

Digital Twins has been defined as a virtual representation of a real system, with validation links capable of granting an association and functional equivalence between the “twins,” even simultaneously or with a real-time delay. The virtual counterpart should be a model that must contain all essential issues, operations, and processes to reproduce...

This study introduces a new approach to represent and analyse particle number size distributions (PNSD) of atmospheric aerosols. Amazonian aerosol data, measured from May 2021 to April 2022 at the Amazon Tall Tower Observatory (ATTO), were fitted by a trimodal lognormal function and the outputs were evaluated by means of the N-Dg-σ phase space. Thi...

New particle formation (NPF) in the tropical free troposphere (FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules (OOMs) produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical ob...

Smoke from vegetation fires affects air quality, atmospheric cycling, and the climate in the Amazon rain forest. A major unknown has remained the quantity of long-range transported smoke from Africa in relation to local and regional fire emissions. Here we quantify the abundance, seasonality, and properties of African smoke in central Amazonia. We...

Urbanization and fires perturb the quantities and composition of fine organic aerosol in the central Amazon, with ramifications for radiative forcing and public health. These disturbances include not only direct emissions of particulates and secondary organic aerosol (SOA) precursors but also changes in the pathways through which biogenic precursor...

New particle formation (NPF) in the tropical free troposphere (FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules (OOMs) produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical ob...

Dimethyl sulfide (DMS) is the primary natural contributor to the atmospheric sulfur burden. Observations concerning the fate of DMS oxidation products after long-range transport in the remote free troposphere are, however, sparse. Here we present quantitative chemical ionization mass spectrometric measurements of DMS and its oxidation products sulf...

Nucleation and condensation associated with biogenic volatile organic compounds (BVOCs) are important aerosol formation pathways, yet their contribution to the upper-tropospheric aerosols remains inconclusive, hindering the understanding of aerosol climate effects. Here, we develop new schemes describing these organic aerosol formation processes in...

As mudanças climáticas constituem um dos maiores desafios da humanidade hoje. É urgente entendermos como os ecossistemas brasileiros, a economia, a infraestrutura, as cadeias produtivas, a biodiversidade, a saúde, entre outros aspectos, estão sendo afetados pelas mudanças climáticas. O Brasil tem vantagens estratégicas enormes, como a possibilidade...

The Amazon Basin is frequently influenced by the trans-Atlantic transport of African dust plumes during its wet season (January–April), which not only interrupts the near-pristine atmospheric condition in that season, but also provides nutrient inputs into the Amazon rainforest associated with dust deposition. The factors controlling the long-range...

The techniques and analyses employed by remote sensing provide key information about atmospheric particle properties at regional and global scales. However, limitations in optical spectral models used to represent the different types of aerosols in the atmosphere and their effects (direct and indirect) are still one of the major causes of sources o...

Dimethyl sulfide (DMS) is the primary natural contributor to the atmospheric sulfur burden. Observations concerning the fate of DMS oxidation products after long-range transport in the remote free troposphere are, however, sparse. Here we present quantitative chemical ionization mass spectrometric measurements of DMS and its oxidation products H2SO...

This study analyses and quantifies the effects of vertical wind shear (VWS) on the properties of shallow cumulus cloud fields over Central Amazonia. We perform idealised simulations with high resolution (50 m horizontally and 20 m vertically) using the Dutch Atmospheric Large-Eddy Simulation (DALES) model, changing the initial conditions and large-...

This study characterized the chemical composition of particulate matter from light- (LDV) and heavy-duty (HDV) vehicles based on two traffic tunnel samplings carried out in the megacity of São Paulo (Brazil), which has >7 million vehicles and intense biofuel use. The samples were collected with high-volume samplers and analyzed using chemical chara...

The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the Amazon Rainforest. Using AERONET (Aerosol Robotic Network) long-term measuremen...

Nucleation and condensation associated with biogenic volatile organic compounds (BVOCs) are important aerosol formation pathways, yet their contribution to the upper tropospheric aerosols remains inconclusive, hindering the understanding of aerosol climate effects. Here, we develop new schemes describing these organic aerosol formation processes in...

The Amazon rainforest suffers increasing pressure from anthropogenic activities. A key aspect not fully understood is how anthropogenic atmospheric emissions within the basin interact with biogenic emissions and impact the forest's atmosphere and biosphere. We combine a high-resolution atmospheric chemical transport model with an improved emissions...

During the dry season of 2014, the formation of a mesoscale convective system (MCS) caused intense precipitation and strong winds in the central Amazon region. In this period, cases of MCS that occurred during the days when there were higher concentrations of CO were analyzed. Through this criterion, a case of MCS occurred on August 16th, 2014 was...

We present a new approach of analyzing and interpreting vertical profiles of cloud microstructure obtained by satellite remote sensing. The method is based on a spectral bin microphysics adiabatic parcel model and aims to elucidate the effects of aerosols on the evolution of convective clouds and related microphysical processes, including the activ...

This Report provides a comprehensive, objective, open, transparent, systematic, and rigorous scientific assessment of the state of the Amazon’s ecosystems, current trends, and their implications for the long-term well-being of the region, as well as opportunities and policy relevant options for conservation and sustainable development.

Plain Language Summary Isoprene is the most abundant non‐methane trace gas emitted from vegetation in the atmosphere. Isoprene reacts with different oxidants forming numerous multifunctional products that affect both ozone and particulate matter concentrations via secondary organic aerosol formation. Day and nighttime isoprene oxidation under pollu...

Characterizing optical properties of aerosols, particularly the absorption processes, is fundamental for understanding the role of these particles in ecosystems as well as the climate, in general. Currently, changes in precipitation regimes in the southern Amazon basin have resulted in a considerable increase in biomass burning, whereby large amoun...

This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observ...

We have measured the concentrations of the water-soluble inorganic aerosol species ammonium (NH+4 ), nitrate (NO− 3 ), chloride (Cl−) and sulfate (SO2− 4 ) at a pasture site in the Amazon Basin (Rondônia, Brazil) from Sept. to Nov. 2002 (LBA-SMOCC). Measurements covered the late dry season (biomass burning), a transition period, and the onset of th...

Dry and wet deposition rates of reactive nitrogen (N) species have been extensively measured in temperate regions. Only few data sets exist about wet N deposition in tropical ecosystems and quantitative experimental information about dry N deposition in tropical environments has been lacking. We estimated wet and dry N deposition rates at a pasture...

We have measured the concentrations of the water-soluble inorganic aerosol species ammonium (NH+4 ), nitrate (NO−3 ), chloride (Cl−) and sulfate (SO2−4 ) at a pasture site in the Amazon Basin (Rondônia, Brazil) from Sept. to Nov. 2002 (LBA-SMOCC). Measurements covered the late dry season (biomass burning), a transition period, and the onset of the...

We have measured the concentrations of the water-soluble inorganic aerosol species ammonium (NH+4 ), nitrate (NO-3 ), chloride (Cl−) and sulfate (SO2−4 ) at a pasture site in the Amazon Basin (Rondônia, Brazil) from Sept. to Nov. 2002 (LBA-SMOCC). Measurements covered the late dry season (biomass burning), a transition period, and the onset of the...

New particle formation (NPF), referring to the nucleation of molecular clusters and their subsequent growth into the cloud condensation nuclei (CCN) size range, is a globally significant and climate-relevant source of atmospheric aerosols. Classical NPF exhibiting continuous growth from a few nanometers to the Aitken mode around 60–70 nm is widely...

During the Cooperative LBA Airborne Regional Experiment 2001 (CLAIRE 2001) within the framework of the Large Scale Biosphere-Atmosphere Experiment in Ama-zonia (LBA), we investigated diel cycles of nitric oxide (NO), nitrogen dioxide (NO 2), ozone (O 3) and carbon dioxide (CO 2) mixing ratios around Manaus, Brazil. Measurements were performed with...

We have measured diurnal and seasonal variations in the mixing ratios of ammonia (NH 3), nitric acid (HNO 3), nitrous acid (HNO 2), hydrochloric acid (HCl) and water-soluble inorganic aerosol species as ammonium (NH 4+), nitrate (NO 3−), nitrite (NO 2−), chloride (Cl −) and sulfate (SO 4 2−) on a pasture site in the Amazon Basin (Rondônia, Brazil)...

This study analyses and quantifies the effects of vertical wind shear (VWS) on the properties of shallow cumulus cloud fields over Central Amazonia. We perform idealized simulations with high resolution (50 m horizontally, 20 m vertically) using the Dutch Atmospheric Large Eddy Simulation (DALES) model, changing the initial conditions and large sca...

The Amazon rainforest is the largest source of isoprene emissions to the atmosphere globally. Under low nitric oxide (NO) conditions (i.e. at NO mixing ratios less than about 40 pptv), isoprene reacts rapidly with hydroxyl (OH) to form isoprene-derived peroxy radicals (ISOPOO), which subsequently react with the hydroperoxyl radical (HO2) to form is...

Aerosol-cloud interactions remain uncertain in assessing climate change. While anthropogenic activities produce copious aerosol nanoparticles smaller than 10 nanometers, they are too small to act as efficient cloud condensation nuclei (CCN). The mechanisms responsible for particle growth to CCN-relevant sizes are poorly understood. Here, we present...